As I don't have a Tumblr account

This kind of ranks up there with the produce I saw growing in a cemetery after attend the funeral of a friend's father. The squashes looked lovely, but I was NOT comfortable with the idea of EATING it. Never mind that it's a private plot, what about the condition of the soil? Yes, squashes grow great, but there are bugs and worms and do we really know how much chemical pollution is seeping into cemeteries from caskets and eventually corpses? Growing life from death is a natural and beautiful thing, but one can't always eat the results.

Re: As I don't have a Tumblr account

I mean, don't get me wrong, cemeteries are actually awesome for some kinds of vegetation--a lot of our super rare prairie plants persist in chunks of cemetery that go unmowed more than once or twice a season, and the margins of some are super-biodiverse because nobody tills or builds on them--those and railway cuts provide an unholy number of rare plants.

But things you eat...uh...no. I mean, on one level, part of me is all "Wow, life from death!" sure, but on another, rather more important level, I am kinda squicked out and I imagine the majority of people in our particular culture would be too.

Anyone who sneers at the idea that neglected fruiting trees attract rodents has never lain awake listening to rats---not little field mice, big Norway rats---squeaking and fighting in the street, in the yard, and on the roof, or heard them chewing their way into the eaves, attracted by a tree full of ripe plums.

Furthermore. "The city" does not plant trees in San Francisco. Individual homeowners and businesses do. They select their street trees (often the organization Friends of the Urban Forest is involved) but property owners have to care for those trees. I hate Callery pear as much as the next horticulturalist, but given a choice between that or nothing, I'll take the fruitless pear.

Finally, many yards in San Francisco have fruit trees already, particularly in older neighborhoods. Apple, pear, plum, many kinds of citrus, and fig are all common. And all are commonly neglected, badly pruned, loaded with fruit that drops and rots. Fruit trees require attendance and few people have the time, resources, or inclination to do so. No one wants to eat rat-bitten fruit covered with brake dust and whatever else is in the air.

One of the Bradford pears just went in the teeny subdivision I'm in--split right in half, as they do. The developer planted one per yard, and I've watched them expire, one by one, over the last seven years. Were I in a tightly cramped area, I'd probably go for no tree at all, just for liability reasons, over a going-to-die-messily Bradford that might land on the neighbor's car. But I'm grumpy about them now.

But yeah, overall, it's not that there is no fruit, it's that people don't know how to tend, harvest, or process it. The lack is not in fruit-beating trees, it's in knowledge and time and skills. Slapping in a graft and walking away going "I've made food!" doesn't help. You've probably just made a mess.

The amount of thriving purslane I see often tempts me, but as it grows absolutely anywhere, it carries that same "ick, what's in this soil?" Mulberries are fair game, though; I once headed an impromptu berry picking session at botanical gardens when some kids saw me trying mulberries from the 100 year old tree (I like to think it was happy to have people harvesting them).

I can see wanting to graft onto a tree near an apartment where the --grafter?-- has intentions to stay in the area for years, but guerilla gardening without being there to see if the plants make it seems counterintuitive--since a garden that dies can be just as much an eyesore as the original milieu--more so, if you imported bags of dirt and full grown plants.

On a more positive note someone in my neighborhood stuck iris plants into neglected spots along my alleyway. Great choice for the Denver climate, they might even bloom without care. Possibly. In good years. I have been inspired by this to consider planting native pussytoes (Antennaria parvifolia) in spots that I free of weeds... Or perhaps some of our local lupines. Or maybe greenthread. Or harebells (if I can figure out how to quickly propagate and transplant them.) Or even grape hyacinths. The last is not a great choice as far as native status goes, but they are survivors. My plants have survived on the same alleyway with zero watering, which is hard on any plant in Denver.

Caveat: different culture

Okay, I went and read the tumblr post, which made sense in some ways (uneaten fruit is pest-bait and street-trash) and ..no sense at all in some others (I mean, fruits -apples!- with worms are inedible? since when?). Different cultural concepts of what is food and what isn't have weight on whether this could be an effective practice (if somebody bothered with follow-ups, that is), but not on actual edibility. This is not why I'll add my voice to the Do Not Do This party.

Beyond the "Will people actually eat the fruit?" question, my concern is that the grafts are done wrong: the grafted branches depart from the main branch at an angle which will, should they do bear fruit, put strain on the branch joining with the main trunk*, which makes it likely that, should the grafted bit carry any load - and apple sorts tend to bear fruit on the very tip, thus adding extra strain - the break point will split the tree. The sensible way to graft anything load-carrying would be to graft the central branch -the one that, in time, will become the tree trunk- so that it will not bring to flexion stress. I am angry for the trees.

*the graft zone will tend to thicken/make a "knot", so it will likely not breach. It may be more prone to fungal rot, dead & alive wood meshing and bacterial cancers, but it still doesn't make it break-prone for the first handful of years.

Re: Caveat: different culture

Look, you've grown up in cities. You have never in your life seen an apple that was not the Platonic supermarket ideal of an apple. Your whole concept of apples is a round, shiny thing with crisp white flesh. (Or it's a Red Delicious, and as a result you don't like apples very much.)

You see this thing on a tree that looks like an apple. You're hungry. You pick it. You take a bite.

It is sour and a little chewy you look at it and THERE IS A THING WIGGLING IN IT.

You have, in fact, just taken a BITE of the thing. Which is in your mouth. Being chewed. And for all you know, laid eggs there, since we can probably assume that the lifecycle of apple worms is not one of your areas of study.

You are now having an experience far more akin to Alien than to Little House On The Prairie. You are not gonna finish the apple. You are not gonna go "Wow, street trees produce edible fruit, thank you, guerilla grafters!" You're gonna wonder if you've been poisoned, if you're going to die, if you're going get parasites. Because you do not have the knowledge base for what just happened. (Which isn't your fault--it's not like they teach you this in school. School's relation to plants is a drawing in a textbook and a lecture on photosynthesis, and maybe if you're lucky, germinating a seed on a wet napkin.)

There are a dozen ways that one could process a wormy apple. But this all requires knowledge and experience and a totally different culture of food than is available to the person who just took the bite.

Nobody's saying wormy apple are inedible, but the gulf you have to overcome for many people to be able to view them as food is a lot bigger than the worm.

I forage on roadsides all the time. I also never take more than 1/5 of what's there from anywhere publicly accessible, so it's hardly a significant part of my diet. also, with the quantity of possibly-harmful chemicals we use in factory farming, being squeamish about roadside fruit strikes me a little odd.

that said, I have one thing to say to people who want to get food growing random places: more milkweed! super tasty, requires no tending, and good for the butterflies.

Squeamish is not the word.

The chemicals we use in industrial farming tend to include things like nerve-toxins as pesticides. They are bad, but they have been approved for use on food plants.

In an old city, there is a whole different level of threat. Land with a tree now could have been a factory 150 years ago, full of industrial poisons like lead, arsenic, mercury, cyanide. Some of these are elemental poisons that never break down.

In my city, the official recommendation is not to eat street fruit unless you've had it tested for safety. If you want to grow vegatables in your yard, build raised beds and bring in your own soil.

That's an interesting difference in how the guerilla gardening movement works. Over here, it seems (certainly in my neck of the woods and in Brighton) that part of the point of the exercise is teaching the homeless and unemployed who want in how to look after the gardens so they have a marketable skill, plus anyone else interested. Just dumping a garden and running would be impolite.

gardening/farming

You are so right on so many levels. Especially the concept of plant and run. Having actually ruined my body trying to hand weed, etc . a small truck farm... the work involved is insane. I have chased off sturdy young male 18 years olds, who couldn't take the strain. The removal of so much of the U.S. populace from any concept of what it takes to grow clean food is terrifying. But flopping down a couple of squash plants and some lettuce and expecting people to water, weed, and harvest is madness.

For a time, the medians in our desert city were planted with a particular kind of cactus that is extremely edible. The pads, once freed of thorns, are very nutritious and the tuna (i.e. the bright pinkred fruits covered in tiny thorns the size of velcro hooks that you're supposed to burn off) tastes wonderful in a variety of things. There were cacti in the medians taller than I were, ancient cacti full of food and nutrients and... no one was eating any save the birds. I know it wasn't the "Is it food?" part of culture because I've seen both cactus pads and the tuna for sale in the grocery store.

In a city with hunger issues, and poverty issues, there was this food and no one was trying to eat it. When I asked my friends, they said they thought it was illegal to eat food grown on city property.

In a city with hunger issues, and poverty issues, there was this food and no one was trying to eat it.

Yes, but there's the issue of shame. Even if someone knew how to process the food properly, and how to make sure it was healthy, there'd still be the embarrassment of having taken food from a public plant. Culturally, it's probably a step above dumpster diving if you aren't a young kid who wouldn't be expected to know better - except with the risk for more embarrassment, because dumpsters, at least, are out of public view and you don't have to worry about someone you know spotting you there.

I do recall that my grade school had some lovely cherry trees lining the front walk, and I think (as in "I recall this being a thing, but it's been nearly two decades now, so I cannot be completely sure") that we were encouraged to take home any of the fruit if we wanted to. On the one or two occasions where I tried it, the cherries were pretty terrible - hard and sour-bitter. So usually they were left on the tree for the birds and insects to have.

On a major road, I would worry about carbon monoxide being in the produce.

A cemetery will not let you plant on top of a grave because the interred may need to be un-interred if the courts believe there is something wrong with the tests routinely done after a death. My local cemetery where more and more of my relatives are ending up explained this to us after we decided my mom needed her favorite rose bush with her for eternity. They said we could put it behind the headstone but nothing could ever be planted on top of a grave because the law would make them remove it as soon as the groundskeepers noticed it.

When I was a child we spent many happy hours each summer raiding the local woods for blackberries. It didn't bother us that the berries often had little grubs inside that came out when the berries were soaked in salt water. We still munched through our fair share while picking them.

However we were discouraged from picking any by the roadside - due to pollution possibly contaminating them.

I've never seen anyone doing guerilla grafting but there is a local cherry tree that regularly converts the pavement below it to a sticky mess every time it fruits. The birds enjoy its yearly bounty but most of the local children complain the fruit is bitter to the taste.

I remember some of the fruit - bearing plants/trees from my childhood as well as the flowering bushes that grew on the hillsides of my childhood home in a suburb Pittsburgh. From the street to our yard were honeysuckle bushes and roses; a flowering crabapple between our house and the house next door; Two dwarf Bing cherry trees in the backyard one of them was severely injured after a neighbor kid whacked it with a metal baseball bat, but the tree kept producing cherries even after my family moved; the hill between my house and the adjacent house behind us was covered with rose bushes that led into a small grape vineyard that produced as well. We also had a small peppermint patch and a small area that grew marvelous dark red peonies in Pittsburgh.

We had a small plum tree here in the backyard of the house we moved to here that was already on its way out the family that lived there before us didn't care for it properly and refused to let the neighbors that did know how to care for such trees touch it due to the fact that the next door neighbors were African-Americans.

Re: city gardens

A much more common thread I have seen in the last few years is community gardens, which is a whole other animal, where the community (or parts of it) care for a garden and residents are free to pick as needed. Which, in my experience in two different inner cities (Saint Paul, MN and Cincinnati, OH), is actually quite effective and strengthens the community. People don't look at it as charity, or shame because it's by the community, for the community.